A serial voltage identification (SVID) bus is a serial synchronous interface often employed in a computing system for transferring power management information between a microprocessor and a voltage regulator device. More specifically, the SVID bus includes a clock line, a data line, and an alert line for communicating voltage identification information and power state information between the microprocessor and the voltage regulator device. Typically, the microprocessor provides the voltage identification information and power state information to the voltage regulator device. In turn, the voltage regulator device regulates the voltage and current supplied to the microprocessor based on the voltage identification and power state information. For example, the voltage regulator device may be a direct-current to direct current (DC-to-DC) converter that also functions as a voltage and current regulator.
Typically, the microprocessor provides voltage identification information indicating a desired operational voltage level of the microprocessor to the DC-to-DC converter. The DC-to-DC converter adjusts its output voltage level based on the voltage identification information. In this way, the microprocessor controls its operational voltage level by providing voltage identification information to the DC-to-DC converter. Moreover, the microprocessor modifies its operational voltage by updating the voltage identification information provided to the DC-to-DC converter. For example, the microprocessor may modify its operational voltage in response to temperature changes or current load changes to minimize power consumption.
Additionally, the microprocessor provides power state information indicating a desired operational current of the microprocessor to the DC-to-DC converter. For example, the power state information may indicate an active mode, idle mode, sleep mode, or power down mode of operation for the microprocessor. The DC-to-DC converter adjusts its available output current level based on the power state information. Moreover, the microprocessor modifies the available output current level of the DC-to-DC converter to minimize power consumption or maximize performance by updating the power state information provided to the DC-to-DC converter.